This book, the catalog for the current blockbuster show at the National Gallery in London, is a wonderful study of Leonardo's Milanese period spent at the Court of the Sforza family. It is therefore not a complete retrospective of the Florentine master's output (don't expect any Annunciation or Mona Lisa here..) but it is centered on a nevertheless absolutely breathtaking body of works that include the Louvre's Belle Ferronière, the Lady with an Ermine from the Czartoryski Museum in Cracow, and the two versions of the Virgin of the Rock. The illustrations are of a great quality (not only of the works by Da Vinci, but also of paintings and drawings by his pupils and assistants), with a profusion of magnified details and drawn studies for the paintings (studies of hands for example), but above all the book is a great read because of the text and the numerous in-depth studies of the paintings. There is even a rediscovery with the portrait of Christ entitled "Salvator Mundi", whose attribution to Da Vinci is explained at length in the book, even though it still remains debatable. Also noteable are the many reproductions of drawings held in the collection of the Queen of England, which are seldom exhibited and reproduced.
The only qualification I would make is the total absence of provenance history for the works, which, in the case of this late discovery, is a regrettable lack of information.